Any one suggest a bluetooth USB dongle that will work with a Sony soundstation?
For me, the best bt compatibility on linux are intel combo wifi and Bluetooth PCIe cards.
As you are searching a USB one, I would take one that explicitly claim compatibility on Linux.
You can also search about the device chipset (if known) on google to spot subjects like this :
The best choice is to take one compatible with rapsberry PI, this should work perfectly
and confirm reading some reviews :
Once compatible with linux, it will probably work without any issue on your audio device.